Control apparatus, control method, communication system, and program for issuing database operation command to operate database

ABSTRACT

A control apparatus includes: a database which stores control information for controlling a network; an interface unit which is connectable to a plurality of modules, each of which operates the control information based on a predetermined algorithm, and which operates the control information responsive to a database operation command issued by any one of the modules; and a control unit which controls packet processing in the network based on the control information configured by an operation executed by any one of the modules.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present invention is based upon and claims the benefit of thepriority of Japanese patent application No. 2012-202113, filed on Sep.13, 2012, the disclosure of which is incorporated herein in its entiretyby reference thereto.

The present invention relates to a network control apparatus, a methodof setting the network control apparatus, and a program. In particular,it relates to: a network control apparatus controlling a group ofswitches managed thereby in a central manner; a method of setting thenetwork control apparatus; and a program.

BACKGROUND

In recent years, a technique referred to as OpenFlow has been proposed(see non patent literature (NPL) 1 and 2). OpenFlow recognizescommunications as end-to-end flows and performs path control, failurerecovery, load balancing, and optimization on a per-flow basis. AnOpenFlow switch according to NPL 2 has a secure channel forcommunication with an OpenFlow controller and operates according to aflow table suitably added or rewritten by the OpenFlow controller. In aflow table, a set of the following three is defined for each flow:matching conditions (Match Fields) against which a packet header ismatched; flow statistical information (Counters); and Instructions thatdefine processing contents (see section “4.1 Flow Table” in NPL 2).

For example, when receiving a packet, the OpenFlow switch searches theflow table for an entry having a matching condition (see “4.3 MatchFields” in NPL 2) that matches header information of the incomingpacket. If, as a result of the search, the OpenFlow switch finds anentry matching the incoming packet, the OpenFlow switch updates the flowstatistical information (Counters) and processes the incoming packetbased on a processing content (packet transmission from a specifiedport, flooding, drop, etc.) written in the Instructions field of theentry. If, as a result of the search, the OpenFlow switch does not findan entry matching the incoming packet, the OpenFlow switch transmits anentry setting request (Packet-In message) to the OpenFlow controller viathe secure channel. Namely, the OpenFlow switch requests the OpenFlowcontroller to transmit control information for processing the incomingpacket. The OpenFlow switch receives a flow entry defining a processingcontent and updates the flow table. In this way, by using an entrystored in the flow table as control information, the OpenFlow switchexecutes packet forwarding.

-   [NPL 1]-   Nick McKeown, and seven others, “OpenFlow: Enabling Innovation in    Campus Networks,” [online], [searched on Jul. 13, 2012], Internet    <URL:http://www.openflow.org/documents/openflow-wp-latest.pdf>-   [NPL 2]-   “OpenFlow Switch Specification” Version 1.0.0 Implemented (Wire    Protocol 0x01), [online], [searched on Jul. 13, 2012], Internet    <URL:http://www.openflow.org/documents/openflow-spec-v1.0.0.pdf>

SUMMARY

The following analysis has been given by the present invention. In acentral-control-type network as typified by OpenFlow in the above NPL 1and 2, detailed control can be executed. However, to cause a controlapparatus corresponding to the OpenFlow controller in the above NPL 1and 2 to execute an intended operation, an operator is required toprogram a control operation of the controller. Programming of thecontroller requires advanced knowledge and skill such as for managementof a network configuration, programming, and configuration of a testenvironment, in addition to basic specifications of NPL 2.

For example, to configure the OpenFlow controller in NPL 2, variousitems need to be set and programmed, including association between eachswitch and a control channel, topology search by LLDP (Link LayerDiscovery Protocol), path calculation, setting of flow entries in aplurality of switches on a path, and management of input/output packetsper switch. For example, to execute programming, an enormous amount ofknowledge and skill is required, such as about API (ApplicationProgramming Interface) relating to topology management and pathcalculation, many functions relating to API, and arguments that need tobe given to these functions.

Thus, even if devices of a central-control-type network are installed,users may not be able to sufficiently utilize the control flexibility.

It is an object of the present invention to provide: a network controlapparatus that can improve the setting easiness (configuration easiness)of a central-control-type network without detriment to the controlflexibility thereof; a method of setting the network control apparatus;and a program.

According to a first aspect, there is provided a control apparatuscontrolling a network. The control apparatus comprises: a database whichstores control information for controlling the network; an interfaceunit which is connectable to a plurality of modules, each of whichoperates the control information based on a predetermined algorithm, andwhich operates the control information responsive to a databaseoperation command issued by any one of the modules; and a control unitwhich controls packet processing in the network based on the controlinformation configured by an operation executed by any one of themodules.

According to a second aspect, there is provided a control method of acontrol apparatus controlling a network. The control method comprises:storing control information for controlling the network in a database;operating the control information responsive to a database operationcommand issued by any one of a plurality of modules, each of whichoperates the control information based on a predetermined algorithm; andcontrolling packet processing in the network based on the controlinformation configured by an operation executed by any one of themodules. This method is associated with a certain machine, that is, withthe control apparatus controlling the network by using the database andmodules.

According to a third aspect, there is provided a communication systemcomprising a control apparatus controlling a network. The controlapparatus comprises: a database which stores control information forcontrolling the network; an interface unit which is connectable to aplurality of modules, each of which operates the control informationbased on a predetermined algorithm, and which operates the controlinformation responsive to a database operation command issued by any oneof the modules; and a control unit which controls packet processing inthe network based on the control information configured by an operationexecuted by any one of the modules.

According to a fourth aspect, there is provided a program causing acontrol apparatus controlling a network to execute processes of: storingcontrol information for controlling the network in a database; operatingthe control information responsive to a database operation commandissued by any one of a plurality of modules, each of which operates thecontrol information based on a predetermined algorithm; and controllingpacket processing in the network based on the control informationconfigured by an operation executed by any one of the modules. Thisprogram can be recorded in a computer-readable (non-transient) storagemedium. Namely, the present invention can be embodied as a computerprogram product.

According to the present invention, the setting easiness (configurationeasiness) of a central-control-type network can be improved, withoutdetriment to the control flexibility thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a configuration of a system according to a firstexemplary embodiment of the present disclosure.

FIG. 2 illustrates a configuration of a control apparatus according tothe first exemplary embodiment of the present disclosure.

FIG. 3 illustrates a configuration of a network DB according to thefirst exemplary embodiment of the present disclosure.

FIG. 4 is a sequence diagram illustrating an operation according to thefirst exemplary embodiment of the present disclosure.

FIG. 5 is a sequence diagram illustrating an operation according to thefirst exemplary embodiment of the present disclosure.

FIG. 6 is a sequence diagram illustrating an operation according to thefirst exemplary embodiment of the present disclosure.

FIG. 7 illustrates a configuration of a network DB according to a secondexemplary embodiment of the present disclosure.

FIG. 8 illustrates a configuration of the network DB according to thesecond exemplary embodiment of the present disclosure.

FIG. 9 illustrates a configuration of the network DB according to thesecond exemplary embodiment of the present disclosure.

FIG. 10 illustrates database operation commands (DB operation commands)used in the second exemplary embodiment of the present disclosure.

FIG. 11 illustrates database operation commands (DB operation commands)used in the second exemplary embodiment of the present disclosure.

FIG. 12 illustrates a configuration of a system according to a thirdexemplary embodiment of the present disclosure.

FIG. 13 illustrates a configuration of an OpenFlow control unitaccording to the third exemplary embodiment of the present disclosure.

FIG. 14 illustrates an operation flow of a network DB by a topologyprocessing unit according to the third exemplary embodiment of thepresent disclosure.

FIG. 15 illustrates an operation flow of the network DB by a flowprocessing unit according to the third exemplary embodiment of thepresent disclosure.

FIG. 16 illustrates an operation flow of the network DB by a packetprocessing unit according to the third exemplary embodiment of thepresent disclosure.

FIG. 17 is a sequence diagram illustrating an operation according to thethird exemplary embodiment of the present disclosure.

FIG. 18 is a sequence diagram illustrating an operation according to thethird exemplary embodiment of the present disclosure.

FIG. 19 is a sequence diagram illustrating an operation according to thethird exemplary embodiment of the present disclosure.

FIG. 20 is a sequence diagram illustrating an operation according to thethird exemplary embodiment of the present disclosure.

FIG. 21 illustrates a configuration of a system according to a fourthexemplary embodiment of the present disclosure.

FIG. 22 illustrates a graphic display of a network topology according tothe fourth exemplary embodiment of the present disclosure.

FIG. 23 illustrates a graphic display of packet processing informationaccording to the fourth exemplary embodiment of the present disclosure.

FIG. 24 illustrates a graphic display of packet input and outputinformation according to the fourth exemplary embodiment of the presentdisclosure.

FIG. 25 illustrates a configuration of a system according to a fifthexemplary embodiment of the present disclosure.

FIG. 26 illustrates a configuration of a system according to a sixthexemplary embodiment of the present disclosure.

FIG. 27 illustrates a configuration of a system according to a seventhexemplary embodiment of the present disclosure.

FIG. 28 illustrates an operation of network DBs by an aggregation logicunit according to the seventh exemplary embodiment of the presentdisclosure.

FIG. 29 illustrates an operation of network DBs by an aggregation logicunit according to the seventh exemplary embodiment of the presentdisclosure.

FIG. 30 illustrates an operation of network DBs by an aggregation logicunit according to the seventh exemplary embodiment of the presentdisclosure.

FIG. 31 illustrates a configuration of a system according to an eighthexemplary embodiment of the present disclosure.

FIG. 32 illustrates an operation of network DBs by an integration logicunit according to the eighth exemplary embodiment of the presentdisclosure.

FIG. 33 illustrates an operation of a network DB by the integrationlogic unit according to the eighth exemplary embodiment of the presentdisclosure.

FIG. 34 illustrates a configuration of a system according to a ninthexemplary embodiment of the present disclosure.

FIG. 35 illustrates a configuration of a component manager of a controlapparatus according to the ninth exemplary embodiment of the presentdisclosure.

FIG. 36 illustrates a configuration of a system according to a tenthexemplary embodiment of the present disclosure.

FIG. 37 illustrates a screen displayed on a display unit according tothe tenth exemplary embodiment of the present disclosure.

FIG. 38 illustrates a correspondence relationship between a useroperation content and a control apparatus configuration according to thetenth exemplary embodiment of the present disclosure.

FIG. 39 illustrates a correspondence relationship between a useroperation content and a control apparatus configuration according to thetenth exemplary embodiment of the present disclosure.

FIG. 40 illustrates a correspondence relationship between a useroperation content and a control apparatus configuration according to thetenth exemplary embodiment of the present disclosure.

FIG. 41 illustrates a correspondence relationship between a useroperation content and a control apparatus configuration according to thetenth exemplary embodiment of the present disclosure.

FIG. 42 illustrates a correspondence relationship between a useroperation content and a control apparatus configuration according to thetenth exemplary embodiment of the present disclosure.

PREFERRED MODES First Exemplary Embodiment

According to a first exemplary embodiment of the present disclosure, acontrol apparatus can control a network in a central manner by operatinga DB (Database) storing control information about a configuration of thenetwork and a method of processing packets in the network, for example.For example, the DB is configured by Key-Value stores and is operatedthrough predetermined DB operation commands. The DB can be operatedthrough simple operation commands such as commands for inputting andoutputting information to and from the DB and a command for deletinginformation in the DB. In the first exemplary embodiment, the controlapparatus can be configured by combining modules that operate the DBthrough operation commands. Thus, the control apparatus according to thefirst exemplary embodiment can be programmed through simple DB operationcommands, without using API or many functions relating thereto.

Next, the first exemplary embodiment will be described in detail withreference to drawings. FIG. 1 illustrates a configuration of acommunication system according to the first exemplary embodiment of thepresent disclosure. In FIG. 1, the communication system is configured bya control apparatus 1, a network DB 2, and a network 4 including aplurality of nodes 3.

The control apparatus 1 controls the network 4 in a central manner byoperating the network DB 2.

Each node 3 in the network 4 processes a packet in accordance with thecontrol apparatus 1.

For example, the network DB 2 is a database configured by Key-Valuestores. For example, the network DB 2 stores identification information(Key) and data (Value) in pairs. In the network DB 2, identificationinformation (Key) is set per data (Value).

FIG. 2 illustrates a configuration of the control apparatus 1. In FIG.2, the control apparatus 1 includes a DB operation logic unit 11, anetwork control unit 12, and a DB interface unit 10 connected to thenetwork DB 2.

The DB interface unit 10 has a function of operating the network DB 2 byusing predetermined DB operation commands issued by the DB operationlogic unit 11. Alternatively, the control apparatus 1 can be configuredby combining a plurality of DB operation logic units 11. Thus, the DBinterface unit 10 can be connected to a plurality of DB operation logicunits 11 (portions indicated by dashed lines in FIG. 2). The DBinterface unit 10 can operate the network DB 2 by using commands issuedfrom the plurality of DB operation logic units 11. The DB interface unit10 can configure information based on a combination of a plurality of DBoperation logic units 11 in the network DB 2. Namely, an operator caneasily change a configuration of the network DB 2 by changing thecombination of the DB operation logic units 11 connected to the DBinterface unit 10. Thus, an operator can easily configure the controlapparatus 1 suitable to a type of the network 4 or to a communicationprotocol used in the network 4.

Examples of the commands for operating the network DB 2 will be listedbelow. However, since the following commands are examples, the DBoperation commands according to the present disclosure are not limitedto the following examples.

Information input/output command

Information deletion command

Notification subscription command

An information input/output command is used for inputting information tothe network DB 2. In addition, an information input/output command isused for acquiring information from the network DB 2. For example, theDB interface unit 10 uses a command “get(key)” to acquire data (Value)corresponding to identification information (key) from the network DB 2.In addition, the DB interface unit 10 uses a command “put(key, value)”to input data (value) corresponding to identification information (Key)to the network DB 2. If data (Value) is listed, the DB interface unit 10may use a command “push(key, value)” or a command “pop(key)” to executeinput or output of data (Value). Namely, data may be used as a queue ora stack.

The information deletion command is used for deleting information fromthe network DB 2. For example, the DB interface unit 10 uses a command“delete(key)” to delete data (value) corresponding to identificationinformation (key) from the network DB 2.

For example, the notification subscription command is used forsubscription. With this command, if an operation corresponding tospecified identification information (key) is executed on the network DB2, the network DB 2 notifies the DB interface unit 10 of data (value)corresponding to the identification information (key). For example, theDB interface unit 10 transmits a command “subscribe(key)” to the networkDB 2, and if an operation corresponding to identification information(key) is executed, the DB interface unit 10 receives data (value)corresponding to the identification information (key) from the networkDB 2. A key pattern such as a wildcard or a regular expression may beused for the identification information. For example, the network DB 2uses a command “publish(key, value, op)” to notify the DB interface unit10 of data (value) corresponding to the identification information. Anoperation (including put/get/delete) corresponding to the key can beincluded in the “op”. After notified, the DB operation logic unit 11 canrecognize addition, acquisition, or deletion of a key corresponding toidentification information.

A plurality of DB operation logic units 11 may share common DB operationcommands. By allowing a plurality of DB operation logic units 11 tooperate the network DB 2 with common commands, a network operator caneasily extend the DB operation logic units 11. Namely, when adding a DBoperation logic unit 11 having a new function to the control apparatus1, an operator does not need to newly design an interface between the DBoperation logic unit 11 and the network DB 2.

The DB operation logic unit 11 has a function of operating informationstored in the network DB 2 based on a predetermined algorithm definedbased on a type of the DB operation logic unit 11. For example, the DBoperation logic unit 11 has a function of inputting information acquiredfrom the network 4 to the network DB 2 via the DB interface unit 10.

The network control unit 12 has a function of controlling the network 4based on the network DB 2 configured by an operation of the DB operationlogic unit 11. For example, the network control unit 12 can changemethods of controlling the network 4, depending on a communicationprotocol used in the network 4.

FIG. 3 illustrates a configuration of the network DB 2. Thisconfiguration in FIG. 3 is an example, and therefore, the configurationof the network DB 2 is not limited to the configuration in FIG. 3.

For example, the network DB 2 includes information about the topology ofthe network 4 (topology information; first information), informationabout a packet processing method (packet processing information; secondinformation), and information about a packet (packet information; third,fourth information).

For example, the topology information includes information about eachnode 3 that exists in the network 4 (node information) and informationabout a link between each node pair (link information). For example, thenode information includes information about identifiers andcommunication ports of the nodes 3. For example, the link informationincludes identifiers of the links, identifiers of the nodes 3 connectedto the links, and identifiers of communication ports of the nodes 3connected to the links.

The packet processing information includes flow information. The flowinformation is information about a flow to which packets belong. A flowsignifies a group of communication packets having a predeterminedattribute (an attribute that can be identified based on a communicationdestination, source, or the like). For example, the flow informationincludes a matching condition, Path information, and processinginformation. For example, the matching condition represents a conditionfor identifying packets corresponding to the flow information. Forexample, the Path information represents a path through which packetsbelonging to the flow matching the matching condition travel. Forexample, the processing information represents a process to be executedon packets that travel through the path corresponding to the Pathinformation (for example, rewriting of header information).

The packet information includes input packet information and outputpacket information. The input packet information is a packet that doesnot match a matching condition in any flow information among the packetsreceived from the network 4. The output packet information is a packetthat needs to be outputted from the network 4.

For example, the topology information, the packet processinginformation, and the input packet information stored in the network DB 2may be standardized in predetermined format. By standardizing theinformation stored in the network DB 2, the network DB 2 can havecompatibility with networks that comply with various protocols.

FIGS. 4 to 6 illustrate operations according to the first exemplaryembodiment. Since the operations in FIGS. 4 to 6 are examples, theoperations according to the present disclosure are not limited to theoperations illustrated in these drawings.

FIGS. 4 to 6 illustrate examples in which the network DB 2 is operatedby a plurality of DB operation logic units 11 (“DB operation logic units11-1 and 11-2”). The DB operation logic unit 11-1 has a function ofoperating the network DB 2 and inputting/outputting information about atopology. The DB operation logic unit 11-2 has a function of generatingpacket processing information based on information stored in the networkDB 2.

FIG. 4 illustrates an operation in which the DB operation logic unit11-1 manages the topology of the network 4 by operating the network DB2.

The DB operation logic unit 11-1 of the control apparatus 1 collectsinformation about the topology from the network 4 via the networkcontrol unit 12 (S10). The information about the topology is collectedby using LLDP (Link Layer Discovery Protocol), for example. LLDP is aprotocol with which apparatuses on a network exchange information withneighboring apparatuses and collect information about neighboringapparatuses connected to communication ports of the apparatuses. Forexample, the network control unit 12 collects information, which hasbeen collected by each node 3 in the network 4 through LLDP, from eachnode 3.

For example, the DB operation logic unit 11-1 generates topologyinformation in predetermined format corresponding to the network DB 2,based on the information collected via the network control unit 12(S11).

By using a DB operation command (information input/output command), theDB operation logic unit 11-1 stores the generated topology informationin the network DB 2 via the DB interface unit 10 (S12).

FIG. 5 illustrates an operation in which the DB operation logic unit11-2 generates information about a method of processing packets flowingin the network 4 by operating the network DB 2.

By using a DB operation command (information input/output command), theDB operation logic unit 11-2 of the control apparatus 1 acquires thetopology information from the network DB 2 via the DB interface unit 10(S13).

The DB operation logic unit 11-2 may preset the network DB 2 by usingthe notification subscription command, so that, when the topologyinformation is changed, the network DB 2 notifies the DB operation logicunit 11-2 of the change of the topology information. When the topologyinformation is changed, the network DB 2 notifies the DB operation logicunit 11-2 of the change of the topology information via the DB interfaceunit 10.

Based on the topology information acquired from the network DB 2, the DBoperation logic unit 11-2 generates packet processing information inpredetermined format corresponding to the network DB 2 (S14). Forexample, the DB operation logic unit 11-2 calculates a packet forwardingpath (“Path information” in FIG. 3) and stores the calculated forwardingpath in the packet processing information. For example, the DB operationlogic unit 11-2 calculates the forwarding path by using a predeterminedcalculation logic. For example, the DB operation logic unit 11-2 setsthe shortest path from a source to a destination to the packetforwarding path.

In addition, the DB operation logic unit 11-2 stores a packet matchingcondition and processing information (rewriting of a header, forexample) in the packet processing information.

By using a DB operation command (information input/output command), theDB operation logic unit 11-2 stores the generated packet processinginformation in the network DB 2 via the DB interface unit 10 (S15).

FIG. 6 illustrates an operation in which the control apparatus 1controls the nodes 3 in the network 4 by operating the network DB 2.

By using a DB operation command (information input/output command), theDB operation logic unit 11-1 of the control apparatus 1 acquires thepacket processing information from the network DB 2 via the DB interfaceunit 10 (S16).

The DB operation logic unit 11-1 may preset the network DB 2 by usingthe notification subscription command, so that, when packet processinginformation is changed, the network DB 2 notifies the DB operation logicunit 11-1 of the change of the packet processing information. Forexample, the DB operation logic unit 11-1 uses the notificationsubscription command to set a notification condition for notification ofupdating of the network DB 2 in the network DB 2. When updating matchingsuch preset notification condition is executed, the network DB 2notifies the DB operation logic unit 11-1 of the updated content of thenetwork DB 2. For example, if the packet processing information ischanged, the network DB 2 notifies the DB operation logic unit 11-1 ofthe change of the packet processing information via the DB interfaceunit 10.

Based on the packet processing information, the DB operation logic unit11-1 generates a processing instruction to be set in a node 3 in thenetwork 4 (information defining a packet processing method executed by anode 3) and sets the processing instruction in the node 3 via thenetwork control unit 12 (S17).

For example, the DB operation logic unit 11-1 refers to the Pathinformation in the packet processing information and sets a processinginstruction in each node 3 on a forwarding path corresponding to thePath information. For example, the DB operation logic unit 11-1 sets aprocessing instruction that defines forwarding of packets from acommunication port corresponding to the forwarding path in each node 3,so that packets are forwarded along the forwarding path corresponding tothe Path information.

As in the above operations illustrated in FIGS. 4 to 6, by operating thenetwork DB 2, the control apparatus 1 can control packet processing inthe network 4 in a central manner.

As described above, by operating the network DB 2 with DB operationcommands, the control apparatus 1 can control the network 4. Thus, anoperator of the network 4 can program the control apparatus 1 bycombining DB operation commands of the network DB 2. The number of DBoperation commands is significantly smaller than the number of commandsrequired for API or functions relating thereto. Thus, an operator of thenetwork 4 can easily program the control apparatus 1, without learningadvanced knowledge and skill.

Second Exemplary Embodiment

Next, a second exemplary embodiment of the present disclosure will bedescribed. In the second exemplary embodiment, a configuration exampleof the network DB 2 and examples of the DB operation commands will bedescribed in detail.

FIGS. 7 to 9 illustrate a configuration of the network DB 2. Theconfiguration in FIGS. 7 to 9 is an example, and therefore, theconfiguration of the network DB 2 is not limited thereto.

In addition, in the second exemplary embodiment, the network DB 2 isconfigured by Key-Value stores. However, the network DB 2 may beconfigured by a different way other than Key-Value stores.

FIG. 7 illustrates topology information stored in the network DB 2. Thetopology information is configured by identification information (Key)about the nodes 3 in the network 4 and identification information (Key)about the links among the nodes 3. Each identification information (Key)is associated with data (Value).

For example, data (Value) corresponding to identification information“/nodes” represents identifiers (node IDs) of the nodes 3 that exist inthe network 4. “{1, 2, 3, 4, . . . }” in FIG. 7 represents a list ofnode identifiers.

“[node_id]” of identification information “/nodes/[node_id]” representsan identifier of one of the nodes 3 that exist in the network 4. Forexample, data (Value) corresponding to the identification information“/nodes/[node_id]” represents information about an identifier used whenthe control apparatus 1 controls the node 3 in the network 4 orinformation about the manufacturing vendor of the node 3. The identifierused when the control apparatus 1 controls the node 3 in the network 4is different from the identifier associated with the aboveidentification information “/nodes”. In the OpenFlow protocol, anidentifier used when the control apparatus 1 controls a node 3 in thenetwork 4 is referred to as DPID (DataPath ID), for example.

For example, data (Value) corresponding to identification information“/nodes/[node_id]/ports” represents a list of identifiers ofcommunication ports of the node 3 corresponding to “[node_id]”. “{1, 2,3, 4, . . . }” in FIG. 7 represents a list of identifiers of thecommunication ports.

“[port_id]” of identification information“/nodes/[node_id]/ports/[port_id]” represents an identifier indicatingone of the communication ports of the node 3 corresponding to“[node_id]”. For example, data (Value) of the identification information“/nodes/[node_id]/ports/[port_id]” includes a port status (for example,a link-up status or a link-down status), a communication bandwidth ofthe port, etc.

For example, data (Value) corresponding to identification information“/links” represents identifiers of the links among the nodes 3 thatexist in the network 4. “{1, 2, 3, 4, . . . }” in FIG. 7 represents alist of link identifiers.

“[link_id]” of identification information “/inks/[link_id]” representsan identifier of one of the links among the nodes that exist in thenetwork 4. For example, data (Value) corresponding to the identificationinformation “/inks/[link_id]” includes information about nodes at bothends of the link and information about communication ports of thesenodes. For example, in FIG. 7, the data (Value) includes an identifier(“src_node_id”) of a packet source node in the link and an identifier(“dst_node_id”) of a packet destination node in the link. In FIG. 7,“src_port_id” represents an identifier of a port corresponding to thelink, among the communication ports of the node corresponding to“src_node_id”. In FIG. 7, “dst_port_id” represents an identifier of aport corresponding to the link, among the communication ports of thenode corresponding to “dst_node_id”.

The network DB 2 manages the topology of the network 4 by using thesedatabase entries illustrated in FIG. 7. By using DB operation commandsand operating the entries illustrated in the FIG. 7, the DB operationlogic unit 11 can manage and operate the topology of the network 4.

FIG. 8 illustrates packet processing information stored in the networkDB 2. For example, the packet processing information includes: amatching condition (Filter) for identifying packets corresponding to thepacket processing information; a forwarding path (Path) for packetsmatching the matching condition; and a predetermined process (Action) tobe applied to the packets matching the matching condition.

Data (Value) corresponding to identification information (“/flows”)represents identifiers of the packet processing information. “{1, 2, 3,4, . . . }” in FIG. 8 represents a list of identifiers of the packetprocessing information.

“[flow_id]” of identification information (“/flows/[flow_id]”)represents an identifier of one of the packet processing information.For example, data (Value) of the identification information“/flows/[flow_id]” includes a matching condition for identifying packetscorresponding to the packet processing information corresponding to“[flow_id]”. For example, when receiving a packet for which a processingmethod is unknown, the DB operation logic unit 11 of the controlapparatus 1 uses a DB operation command to search the network DB 2 forpacket processing information having a matching condition correspondingto the packet. The network DB 2 refers to information about the packet(for example, header information) and notifies the DB operation logicunit 11 of packet processing information having a matching conditioncorresponding to the packet. Based on the supplied packet processinginformation, the DB operation logic unit 11 instructs the node 3 in thenetwork 4 to process the packet.

There are cases where the network DB 2 does not have a DB operationcommand for referring to information about the packet (for example,header information) and searching for packet processing informationhaving a matching condition corresponding to the packet. In such cases,the DB operation logic unit 11 of the control apparatus 1 may use a DBoperation command to read necessary packet processing information fromthe network DB 2 and store the information in advance. In this way, theDB operation logic unit 11 can determine corresponding packet processinginformation by simply referring to information about the packet. Basedon the determined packet processing information, the DB operation logicunit 11 gives an instruction about packet processing to the node 3 inthe network 4.

Data (Value) corresponding to the identification information“/flows/[flow_id]” includes a forwarding path (“Path”) for packetsmatching the matching condition and a process (“Action”) to be executedon the packets matching the matching condition. The DB operation logicunit 11 notifies nodes 3 in the network 4 of an instruction forforwarding the packet, so that the packet is forwarded along theforwarding path defined in the packet processing information. Inaddition, if a process (“Action”) to be executed on a packet exists, theDB operation logic unit 11 instructs the nodes 3 in the network 4 toexecute the process.

FIG. 9 illustrates database entries about packets forwarded to thecontrol apparatus 1 as packets for which a processing method isundetermined. The network DB 2 can manage information about packets forwhich a processing method is undetermined as database entries.

Data (Value) corresponding to identification information “/packets/in”represents a list of identifiers of packets forwarded to the controlapparatus 1 as packets for which a packet processing method isundetermined. For example, the identifier list is used as a queue ofFIFO (First In First Out), by using a DB operation command “push_tail”for adding a value to the end of the list and a DB operation command“pop_head” for extracting a value from the top of the list.

For example, data (Value) of identification information“/packets/in/[packet_id]” includes an identifier of a packet, thereception time of the packet, an identifier of a node 3 that hasreceived the packet, and an identifier of a communication port of thepacket reception node 3.

For example, if a packet is forwarded to the control apparatus 1, the DBoperation logic unit 11 uses a DB operation command to store informationabout the packet in the network DB 2.

Data (Value) corresponding to identification information “/packets/out”represents a list of identifiers of packets, for which a processingmethod has been determined and which need to be returned to the network4 from the control apparatus 1. For example, among the packets stored inthe queue corresponding to “/packets/in”, packets for which a processingmethod has been determined are stored in the queue corresponding to“/packets/out”. For example, data (Value) corresponding to“/packets/out” is a list and is used as a FIFO-type queue.

For example, data (Value) corresponding to identification information“/packets/out/[packet_id]” includes an identifier of a node to which apacket is returned from the control apparatus 1, an identifier of a portto which the packet is returned among the communication ports of thenode, and data stored in the packet (namely, the packet itself).

For example, the DB operation logic unit 11 uses the notificationsubscription command to operate the network DB 2, so that, if a packetis stored in the queue corresponding to “/packets/out” and if the key“/packets/out” is operated, the DB operation logic unit 11 is notified.If a packet is stored in a queue (namely, if an entry corresponding to“/packets/out” and “/packets/out/[packet_id]” is updated), the networkDB 2 notifies the DB operation logic unit 11 of updating of the datacorresponding to “/packets/out/[packet_id]”.

A packet stored in the identification information “/packets/out/” and“/packets/out/[packet_id]” may not correspond to a packet stored in thequeue corresponding to “/packets/in”. In this way, the control apparatus1 can actively output packets.

FIGS. 10 and 11 illustrate DB operation commands used when the DBoperation logic unit 11 operates the network DB 2. As illustrated inFIGS. 10 and 11, by using push commands and pop commands, operationssuch as data insertion and acquisition from an arbitrary position of thelist can be executed. In addition, for example, the control apparatus 1uses a subscribe command to be notified of change of an entry having acertain key in the database. In addition, for example, commands such asget, put, and delete are used to acquire, set, and delete detailedinformation about or a value of the node, link, flow, and packet.

By using these DB operation commands illustrated in FIGS. 10 and 11 andoperating the network DB 2 configured as illustrated in FIGS. 7 to 9,the DB operation logic unit 11 can control the network 4 in a centralmanner. Thus, by using the DB operation commands and combining operationinstructions for the network DB 2, an operator can program the controlapparatus 1. The number of DB operation commands is greatly smaller thanthe number of commands required for API or functions relating theretoused in general programming. Thus, an operator can program the controlapparatus 1 very easily, as compared with general programming.

Third Exemplary Embodiment

Next, a third exemplary embodiment of the present disclosure will bedescribed. The DB operation logic unit 11 can be implemented by a modulehaving various functions. In the third exemplary embodiment, an OpenFlowcontrol unit 11A is arranged as the DB operation logic unit 11.

FIG. 12 illustrates a configuration of a system according to the thirdexemplary embodiment. The OpenFlow control unit 11A has a function ofcontrolling the network 4 based on the OpenFlow protocol. The thirdexemplary embodiment will be described assuming that the network 4 isconfigured by nodes 3 compatible with the OpenFlow protocol. In thethird exemplary embodiment, as needed, the network 4 will be referred toas an OpenFlow network.

FIG. 13 illustrates a configuration of the OpenFlow control unit 11A.The OpenFlow control unit 11A includes a topology processing unit 110, aflow processing unit 111, and a packet processing unit 112.

The topology processing unit 110 uses a DB operation command to operatethe network DB 2 via the DB interface unit 10. For example, the topologyprocessing unit 110 operates the network DB 2 to set topologyinformation in the network DB 2. In addition, for example, the topologyprocessing unit 110 operates the network DB 2 to acquire topologyinformation from the network DB 2.

FIG. 14 illustrates an operation example in which the topologyprocessing unit 110 operates the network DB 2. The topology processingunit 110 uses a command “push_tail(/nodes)” to add an identifier of anode added to the OpenFlow network to the end of the entry list“/nodes”. In addition, the topology processing unit 110 uses a command“put(/nodes/[node_id], <node_info>)” to add information corresponding to“<node_info>”, which is an argument of the command, to the entry“/nodes/[node_id]” ([node_id] is an identifier of the node added to theentry “/nodes”). For example, the topology processing unit 110 addsinformation described in the first exemplary embodiment to the entry“/nodes/[node_id]”.

By using a command “push_tail(/nodes, <node_info>)” instead of the abovecommand “push_tail(/nodes)”, the above series of operations can beexecuted collectively. In such case, execution of the command“put(/nodes/[node_id], <node_info>)” can be omitted.

The topology processing unit 110 uses a command “push_tail(/links)” toadd an identifier of an inter-node link added to the OpenFlow network tothe end of the entry list “/links”. In addition, the topology processingunit 110 uses a command “put(/links/[link_id], <link_info>)” to addinformation corresponding to “<link_info>”, which is an argument of thecommand, to the entry “/inks/[link_id]” ([link_id] is an identifier ofthe link added to the entry “/links”). For example, the topologyprocessing unit 110 adds information described in the first exemplaryembodiment to the entry “/inks/[link_id]”.

By using a command “push_tail(/links, <link_info>)” instead of the abovecommand “push_tail(/links)”, the above series of operations can beexecuted collectively. In such case, execution of the command“put(/inks/[link_id], <link_info>)” can be omitted.

If a node or a link is deleted from the OpenFlow network, the topologyprocessing unit 110 uses a command “pop_at” to delete an identifier ofthe deleted node or link from the node or link list. If a node or a linkis deleted from the OpenFlow network, the topology processing unit 110uses a command “delete” to delete an entry corresponding to the deletednode or link from the network DB 2.

By using the command “pop_at”, the above series of operations can beexecuted collectively. Thus, execution of the command “delete” can beomitted.

By using a command “get”, the topology processing unit 110 acquires data(value) corresponding to specified identification information (key).

The flow processing unit 111 uses a DB operation command to operate thenetwork DB 2 via the DB interface unit 10. For example, the flowprocessing unit 111 operates the network DB 2 to set packet processinginformation in the network DB 2. In addition, for example, the flowprocessing unit 111 operates the network DB 2 to search the network DB 2for packet processing information corresponding to a packet for which aprocessing method is unknown.

FIG. 15 illustrates an operation example in which the flow processingunit 111 operates the network DB 2. If the control apparatus 1 receivesa packet for which a processing method is unknown from the OpenFlownetwork, the flow processing unit 111 receives a request for searchingfor a processing method for the packet from the packet processing unit112. For example, the packet processing unit 112 uses a command“get_matching_flow(<packet_info>)” to request the flow processing unit111 to search for a processing method for the packet. “<packet_info>”,which is an argument of the command, is information about the packet forwhich a processing method is unknown (for example, header information orthe packet itself).

Based on the request from the packet processing unit 112, the flowprocessing unit 111 searches the network DB 2 for packet processinginformation having a matching condition corresponding to“<packet_info>”. The flow processing unit 111 receives the identifier(“flow_id”) of the retrieved packet processing information from thenetwork DB 2. For example, based on the received identifier and by usinga command “get(/flows/[flow_id])”, the flow processing unit 111 acquiresthe packet processing information. The flow processing unit 111 suppliesthe packet processing information to the packet processing unit 112. Ifsuch packet processing information matching the search condition doesnot exist, the flow processing unit 111 notifies to that effect to thepacket processing unit 112.

If the network DB 2 does not have a command for searching for packetprocessing information having a matching condition corresponding to“<packet_info>”, the flow processing unit 111 may use a DB operationcommand to read necessary packet processing information from the networkDB 2 and store the information in advance. In this way, the flowprocessing unit 111 can determine corresponding packet processinginformation by referring to information about the packet.

If no corresponding packet processing information exists, the packetprocessing unit 112 uses a command “push_tail(/packets/in,<packet_info>)” to add the received packet to the network DB 2.

If a corresponding packet processing information exists, the packetprocessing unit 112 requests the flow processing unit 111 to process thepacket.

Based on the acquired packet processing information, the flow processingunit 111 sets a packet handling operation (i.e., packet processing rule)in a node 3 in the OpenFlow network and simultaneously causes the node 3to output the received packet from an appropriate node communicationport of the node 3 based on the packet processing information.

For example, a packet handling operation is information in formatdefined based on the OpenFlow protocol and is used for causing a node 3to process a packet. A packet handling operation includes anidentification condition for identifying a packet received by a node 3and a method for processing a packet matching the identificationcondition. The flow processing unit 111 sets a packet handling operationin a node 3 and the node 3 stores the set packet handling operation in amemory. The node 3 searches the memory for a packet handling operationhaving an identification condition matching the received packet. If thenode 3 finds a packet handling operation having an identificationcondition matching the received packet, based on the retrieved packethandling operation, the node 3 processes the received packet (forwardsthe packet through a communication port specified by the packet handlingoperation, for example).

For example, the flow processing unit 111 sets the identificationcondition in the packet handling operation, based on the matchingcondition included in the packet processing information.

Based on path information (Path) included in the packet processinginformation, the flow processing unit 111 recognizes a packet forwardingpath in the OpenFlow network. The flow processing unit 111 notifiesnodes 3 on the packet forwarding path of the packet handling operation.Based on the packet handling operation, the flow processing unit 111 caninstruct each node 3 on the forwarding path to forward a packet alongthe forwarding path corresponding to the packet processing information.Namely, when the flow processing unit 111 instructs the nodes 3 toforward a packet, the packet handling operation set in each node 3includes a processing method for forwarding a packet through acommunication port corresponding to the forwarding path.

If the packet processing information includes a predetermined process(Action) that needs to be executed on the packet, for example, the flowprocessing unit 111 determines a node 3 that needs to execute thepredetermined process (Action). The flow processing unit 111 sets apacket handling operation, in which a process determined as apredetermined process (for example, header rewriting orencapsulation/decapsulation) is defined, in the determined node 3.

For example, the flow processing unit 111 uses the command “subscribe”,so that, when predetermined updating is executed in the network DB 2(updating of packet processing information or link information), thenetwork DB 2 notifies the flow processing unit 111 of information aboutthe updating. If information specified by the command “subscribe” isupdated, the network DB 2 uses the command “publish” to notify the flowprocessing unit 111 of the information. For example, based on theinformation supplied by using the command “publish,” the flow processingunit 111 determines whether to change a packet handling operationalready set in a node 3 in the OpenFlow network. If change of a packethandling operation is necessary, the flow processing unit 111 generatesand sets a new packet handling operation in the node 3.

If a link or a node in the OpenFlow network is deleted, for example, theflow processing unit 111 deletes packet processing informationcorresponding to the deleted link or node from the network DB 2. Forexample, the flow processing unit 111 deletes packet processinginformation including the forwarding path on which the deleted link ornode is arranged from the network DB 2.

The flow processing unit 111 uses the command “pop_at” to delete anidentifier corresponding to packet processing information that needs tobe deleted from the list of packet processing information. The flowprocessing unit 111 uses the command “delete” to delete an entry(“/flows/[flow_id]”) corresponding to the packet processing information.For example, the flow processing unit 111 generates new packetprocessing information that replaces the deleted packet processinginformation, uses a command “push_at”, and stores the generated packetprocessing information in the network DB 2.

By using the command “pop_at”, the above series of operations can beexecuted collectively. Thus, execution of the command “delete” can beomitted.

The packet processing unit 112 uses a DB operation command to operatethe network DB 2 via the DB interface unit 10. For example, the packetprocessing unit 112 operates the network DB 2 to set information about apacket in the network DB 2.

FIG. 16 illustrates an operation example in which the packet processingunit 112 operates the network DB 2. For example, when receiving a packetfor which a processing method is unknown from the OpenFlow network, thepacket processing unit 112 requests the flow processing unit 111 for aprocessing method corresponding to the packet. As described above, forexample, the packet processing unit 112 uses the command“get_matching_flow(<packet_info>)” to request the flow processing unit111 to search for a packet processing method.

If the packet processing unit 112 is notified by the flow processingunit 111 that packet processing information corresponding to the packetdoes not exist, the packet processing unit 112 registers informationabout the packet in the network DB 2. For example, the packet processingunit 112 uses the command “push_tail(/packets/in)” to register anidentifier of the packet in the end of the entry list “/packets/in”. Inaddition, the packet processing unit 112 uses a command“put(/packets/in/[packet_id], <packet_info>)” to add informationcorresponding to “<packet_info>”, which is an argument of the command,to the entry “/packets/in/[packet_id]” ([packet_id] is an identifier ofthe packet added to the entry /packets/in).

By using a command “push_tail(/packets/in, <node_info>)” instead of theabove command “push_tail(/packets/in)”, the above series of operationscan be executed collectively. In such case, execution of the command“put(/packets/in/[node_id], <packet_info>)” can be omitted.

If packet processing information corresponding to the packet added tothe entry “/packets/in” is generated, the packet is added to the entry“/packets/out”. For example, the packet processing unit 112 sets thenetwork DB 2 in advance, so that, if the command “subscribe” is used andif a packet is added to the entry “/packets/out”, the network DB 2notifies the packet processing unit 112 of information about updating ofthe entry “/packets/out”. For example, the packet processing unit 112uses the command “publish”, so that, if the entry “/packets/out” isupdated, the packet processing unit 112 receives a changed key from thenetwork DB 2. In this way, the packet processing unit 112 can recognizean identifier of the packet that has been registered in the entry“/packets/out”. For example, if the flow processing unit 111 sets apacket handling operation in a node in the OpenFlow network, the packetprocessing unit 112 transmits a packet corresponding to the receivedidentifier to the OpenFlow network. In addition, the packet processingunit 112 uses a command “pop_at(/packets/out, <packet_id>)” to deletethe received identifier from the entry “/packets/out” and uses thecommand “delete” to delete the entry “/packets/out/[packet_id]”.

If a command “pop_head(/packets/out)” is used instead of the abovecommand “pop_at”, packet information can be received from the top of“/packets_out” and the entry “/packets/out/[packet_id]” can be deleted.Thus, execution of the above command “delete” can be omitted.

FIGS. 17 to 20 are sequence diagrams illustrating operations accordingto the third exemplary embodiment.

FIG. 17 illustrates an operation executed when a node is added to thenetwork 4. The topology processing unit 110 detects addition of a nodeto the OpenFlow network and collects information about the added node.

For example, the topology processing unit 110 uses the command“push_tail(/nodes)” to add the node to the entry list “/nodes” in thenetwork DB 2. After adding the node to the list, the topology processingunit 110 receives “node_id” which is an identifier of the node in thenetwork DB 2 from the network DB 2.

For example, the topology processing unit 110 uses the command “put” toadd information about the node to entries in the network DB 2. Forexample, the information about the node added is information about thenode and information about a communication port of the node.

FIG. 18 illustrates an operation executed when a node is deleted fromthe network 4. The topology processing unit 110 detects deletion of anode from the OpenFlow network and collects information about thedeleted node.

For example, the topology processing unit 110 uses the command “pop_at”to delete an identifier corresponding to the deleted node from the entrylist “/nodes”. In addition, the topology processing unit 110 uses thecommand “pop_at” to delete an identifier of the link relating to thedeleted node from the entry list “/links”.

For example, the topology processing unit 110 uses the command “delete”to delete information about the node deleted from the OpenFlow networkand information about the link relating to the deleted node.

FIG. 19 illustrates an operation executed when a link is added to thenetwork 4 and an operation executed when a link is deleted from thenetwork 4. The topology processing unit 110 detects addition of a linkto the OpenFlow network and collects information about the added link.

For example, the topology processing unit 110 uses the command“push_tail” to add the link to the entry “/links”. After adding the linkto the entry list “/links”, the topology processing unit 110 receives anidentifier of the link added to the list from the network DB 2. Based onthe received identifier, the topology processing unit 110 uses thecommand “put” to register information about link added to the OpenFlownetwork to the entry “/inks/[link_id]”.

The topology processing unit 110 detects deletion of the link from theOpenFlow network and collects information about the deleted link.

For example, the topology processing unit 110 uses the command “delete”to delete the entry “/inks/[link_id]” of the deleted link from thenetwork DB 2. In addition, for example, the topology processing unit 110uses the command “pop_at” to delete an identifier of the link deletedfrom the entry list “/links”.

FIG. 20 is a sequence diagram illustrating an operation in which theOpenFlow control unit 11A controls the OpenFlow network based on packetprocessing information included in the network DB 2. The packetprocessing unit 112 receives a packet for which a packet processingmethod is unknown from the OpenFlow network (“packet_in” in FIG. 20).For example, the packet processing unit 112 uses the command“get_matching_flow(<packet_info>)” to query the flow processing unit 111about packet processing information corresponding to the receivedpacket.

For example, the flow processing unit 111 searches the network DB 2 forthe entry (“/flows/[flow_id]”) having a matching condition matching thepacket information (“packet_info”) included in“get_matching_flow(<packet_info>)”.

If the flow processing unit 111 finds packet processing informationmatching the packet received by the packet processing unit 112, forexample, the flow processing unit 111 generates a packet handlingoperation (processing rule) to be set in a node 3 in the network 4 andnotifies the node 3 of the packet handling operation via the packetprocessing unit 112. In addition to notifying the node 3 of the packethandling operation, the packet processing unit 112 returns the packetreceived from the network 4 to the network 4 (“packet_out” in FIG. 20).

If the flow processing unit 111 does not find packet processinginformation matching the packet received by the packet processing unit112, the flow processing unit 111 uses the command “push_tail” to addthe packet received by the packet processing unit 112 to the entry“/packets/in”. After adding the packet to the entry “/packets/in”, theflow processing unit 111 receives an identifier of the packet added tothe entry from the network DB 2 (“packet_id” in FIG. 20). Based on thereceived identifier, the flow processing unit 111 uses the command “put”to add information about the packet received by the packet processingunit 112 to the entry “/packets/in/[packet_id]”.

Fourth Exemplary Embodiment

Next, a fourth exemplary embodiment of the present disclosure will bedescribed. In the fourth exemplary embodiment, an example in which thecontrol apparatus 1 operates the network DB 2 by using a visualizationDB operation logic unit 11B will be described.

To support an operator managing the network 4 with the control apparatus1, the visualization DB operation logic unit 11B has a function ofgraphically displaying at least part of the information stored in thenetwork DB 2 so that the information can be grasped visually.

FIG. 21 illustrates a configuration according to the fourth exemplaryembodiment. The visualization DB operation logic unit 11B in FIG. 21acquires topology information from the network DB 2 and displays aconnection relationship of nodes and links on a display device. Forexample, as illustrated in FIG. 22, the visualization DB operation logicunit 11B graphically displays a network topology. A number allocated toeach node represents an identifier of the node. In addition, a numberallocated to each link represents an identifier of the link. When thenetwork DB 2 notifies the visualization DB operation logic unit 11B ofchange of the topology information, based on this notification, thevisualization DB operation logic unit 11B acquires node and linkinformation from the network DB 2 and changes the displayed connectionrelationship of nodes and links.

In this way, by connecting the visualization DB operation logic unit 11Bin FIG. 21 to the network DB 2, the operator can acquire a configurationof the management target network as visual information. In addition, thevisualization DB operation logic unit 11B can graphically display packetprocessing information in the network DB 2. For example, thevisualization DB operation logic unit 11B superimposes path information(Path) included in the entry “/flows/[flow_id]” on thegraphically-displayed topology. FIG. 23 illustratesgraphically-displayed packet processing information. In FIG. 23, anentry “/flows/10” having identifier “10” is graphically displayed.Information about the nodes and links through which packets travel andinformation about the direction in which the packets are forwarded aregraphically displayed.

As illustrated in FIG. 24, the visualization DB operation logic unit 11Bcan graphically display the entries “/packets/in/[packet_id]” and“/packets/out/[packet_id]”.

Fifth Exemplary Embodiment

Next, a fifth exemplary embodiment of the present disclosure will bedescribed. In the fifth exemplary embodiment, an example in which thecontrol apparatus 1 operates the network DB 2 by using a slice logicunit 11C.

FIG. 25 illustrates a configuration according to the fifth exemplaryembodiment. The slice logic unit 11C in FIG. 25 has a function ofduplicating the network DB 2 to execute network slicing (virtualdivision). The slice logic unit 11C expands a state or change of asingle network DB 2 to a plurality of network DBs 2A and 2B and feeds astate or change of the plurality of network DBs 2A and 2B back to theoriginal network DB 2. In FIG. 25, the control apparatus 1 includes twonetwork DB interface units 10-1 and 10-2. However, a network DBinterface unit may be arranged for each network DB. Alternatively, asingle network DB interface unit may be connected to a plurality ofnetwork DBs 2.

As described above, by connecting the slice logic unit 11C to arbitrarynetwork DBs 2, each of a plurality of network operators (network users)can manage a sliced network as a dedicated network. For example, asuperior network operator can manage the network DB 2 and subordinatenetwork operators permitted by the superior network operator can managethe network DBs 2A and 2B.

Sixth Exemplary Embodiment

Next, a sixth exemplary embodiment of the present disclosure will bedescribed. In the sixth exemplary embodiment, an example in which thecontrol apparatus 1 operates the network DB 2 by using a shortest pathlogic unit 11D will be described. The shortest path logic unit 11D has afunction of calculating the shortest path among the paths from a packetforwarding source to destination in the network 4.

FIG. 26 illustrates a configuration according to the sixth exemplaryembodiment. Based on topology information acquired from the network DB 2and host information read from a host information storage unit 21, theshortest path logic unit 11D in FIG. 26 calculates the shortestforwarding path between arbitrary hosts and stores the shortestforwarding path in a shortest path storage unit 20.

When the network DB 2 notifies the shortest path logic unit 11D ofupdating of a topology-related entry, based on the content of theupdating, the shortest path logic unit 11D recalculates the shortestpath and updates the shortest path storage unit 20. For example, theshortest path logic unit 11D uses the command “subscribe”, so that, ifthe entry “/nodes” or “/links” is updated, the network DB 2 notifies theshortest path logic unit 11D of the updated information.

If an entry specified by the command “subscribe” is updated, the networkDB 2 uses the command “publish” to notify the shortest path logic unit11D of information about the entry. When receiving a notification aboutupdating of topology information from the network DB 2, the shortestpath logic unit 11D recalculates the shortest path corresponding to thenew topology information and stores the shortest path in the shortestpath storage unit 20. The shortest path logic unit 11D may update packetprocessing information when recalculating the shortest path. Forexample, path information (“Path information”) included in the packetprocessing information is updated when recalculating the shortest path.For example, the shortest path logic unit 11D uses the command “put” tostore the updated packet processing information in the entry“/flows/[flow_id]” in the network DB 2.

As described above, by connecting the control apparatus 1 having theshortest path logic unit 11D in FIG. 26 to the network DB 2, a functionof calculating the shortest path and a function of updating packetprocessing information corresponding to this shortest path are added tothe control apparatus 1.

Seventh Exemplary Embodiment

Next, a seventh exemplary embodiment of the present disclosure will bedescribed. In the seventh exemplary embodiment, an example in which thecontrol apparatus 1 operates the network DB 2 by using an aggregationlogic unit 11E will be described. The aggregation logic unit 11E has afunction of aggregating a plurality of nodes and a plurality of links toabstract a network topology.

FIG. 27 illustrates a configuration according to the seventh exemplaryembodiment. For example, the aggregation logic unit 11E in FIG. 27abstracts topology information stored in the network DB 2 and stores theabstracted topology information in a network DB 2C.

For example, the aggregation logic unit 11E operates the network DBs 2and 2C via DB interface units 10-3 and 10-4, respectively.

FIG. 28 outlines an operation in which the aggregation logic unit 11Eabstracts topology information in the network DB 2 and stores theabstracted topology information in the network DB 2C. For example, theaggregation logic unit 11E abstracts topology information in accordancewith an operation by an operator. In FIG. 28, among the topologyinformation stored in the network DB 2, the aggregation logic unit 11Eaggregates and abstracts nodes 1 and 2 and aggregates and abstractsnodes 3 and 4. A new node generated by aggregating the nodes 1 and 2corresponds to a node 1 that is stored in the network DB 2C. A new nodegenerated by aggregating the nodes 3 and 4 corresponds to a node 2 thatis stored in the network DB 2C.

FIGS. 29 and 30 illustrate entries in the network DBs 2 and 2C,respectively. The aggregation logic unit 11E aggregates entries“/nodes/1” and “/nodes/2” in FIG. 29. In addition, the aggregation logicunit 11E aggregates entries “/nodes/3” and “/nodes/4” in FIG. 29. Bythese aggregation operations, the number of nodes to be stored in thenetwork DB 2C is abstracted to “3.”

For example, the aggregation logic unit 11E uses the command “push” toadd three abstracted nodes to the entry “/nodes” in the network DB 2C.As illustrated in FIG. 30, by the aggregation operations, data (Value)of the entry “/nodes” in the network DB 2C is updated to “{1, 2, 3}”.For example, the aggregation logic unit 11E uses the command “put” tostore information about each of the abstracted nodes in the entry“/nodes/[node_id]” in the network DB 2C. For example, the aggregationlogic unit 11E registers IDs (“node ID” in FIGS. 29 and 30) used whenthe control apparatus 1 controls the nodes in the entry“/nodes/[node_id]”. In addition, if a node that is registered in theentry “/nodes/[node_id]” is an abstracted node, the aggregation logicunit 11E registers an ID before the node is abstracted (“original” inFIG. 30) in the entry “/nodes/[node_id]”.

In FIG. 30, “node ID(a)” and “node ID(b)” are allocated as the IDs ofthe two nodes generated by the abstraction. In addition, a nodecorresponding to an entry “/nodes/5” in the network DB 2 is registeredin an entry “/nodes/3” in the network DB 2C. “node ID(c)” is allocatedas the node ID of the entry “/nodes/3” in the network DB 2C.

For example, the aggregation logic unit 11E also aggregatescorresponding links when aggregating nodes. For example, in FIGS. 29 and30, the aggregation logic unit 11E aggregates links corresponding to“/links/2” and “/links/4” in FIG. 29 to “/links/1” in FIG. 30. Forexample, the aggregation logic unit 11E uses the command “put” to storedata (Value) corresponding to “/links/2” and “/links/4” in FIG. 29 inthe entry “/links/1” in the network DB 2C. In addition, the aggregationlogic unit 11E does not register the link (“/links/1” in FIG. 29), whichhas been made no longer necessary by the aggregation of “/nodes/1” and“/nodes/2” in FIG. 29, in the network DB 2C. For example, in FIG. 29,“{src_node: A, dst_node: B}” represents a link in which a packet isforwarded from the node having a node ID(A) to the node having a nodeID(B).

As described above, the aggregation logic unit 11E can abstract atopology. Namely, an operator can control a management target networkbased on an abstracted topology and can easily manage the network.

Eighth Exemplary Embodiment

Next, an eighth exemplary embodiment of the present disclosure will bedescribed. In the eighth exemplary embodiment, an example in which thecontrol apparatus 1 operates the network DB 2 by using an integrationlogic unit 11F will be described. The integration logic unit 11F has afunction of integrating topology information included in a plurality ofnetwork DBs.

FIG. 31 illustrates a configuration according to the eighth exemplaryembodiment. The integration logic unit 11F in FIG. 31 integratestopology information included in network DBs 2D and 2E and stores theintegrated topology information in a network DB 2F.

FIG. 32 illustrates topology information stored in the network DB 2D andinformation stored in the network DB 2E. The network DB 2D includestopology information configured by three nodes (nodes 1-3) and threelinks (links 1-3). The network DB 2E includes topology informationconfigured by three nodes (nodes 1-3) and three links (links 1-3).

FIG. 33 illustrates new topology information generated by integratingthe topology information in the network DBs 2D and 2E.

As illustrated in FIGS. 32 and 33, by integrating the two topologies,six nodes are stored in the network DB 2F. For example, the integrationlogic unit 11F uses the command “push” to store the node list in theentry “/nodes”. By causing the integration logic unit 11F to operate thenetwork DB 2F with the command “push”, the list of integrated nodes(“{1, 2, 3, 4, 5, 6}”) is stored in the entry “/nodes”. In addition, forexample, the integration logic unit 11F uses the command “put” to storeinformation about the nodes in the entry “/nodes/[node_id]”.

As illustrated in FIGS. 32 and 33, by integrating the two topologies,seven links are stored in the network DB 2F. For example, theintegration logic unit 11F uses the command “push” to store the linklist in the entry “/links”. By causing the integration logic unit 11F tooperate the network DB 2F with the command “push”, the list ofintegrated nodes (“{1, 2, 3, 4, 5, 6, 7}”) is stored in the entry“/links”. In addition, for example, the integration logic unit 11F usesthe command “put” to store information about the links in the entry“/inks/[link_id]”.

Ninth Exemplary Embodiment

Next, a ninth exemplary embodiment of the present disclosure will bedescribed. An operator can manage network DBs 2 or DB operation logicunits 11 (or the components 11A-11F described in the third to eighthexemplary embodiments) by using functions of a component manager 30. Thecomponent manager 30 will be described in the ninth exemplaryembodiment.

FIG. 34 illustrates a configuration of a system according to the ninthexemplary embodiment. An operator manages network DBs 2 and DB operationlogic units 11 by using functions of the component manager 30. Inaddition, as illustrated in FIG. 34, even when network DBs 2 and DBoperation logic units 11 are arranged in a plurality of servers (servers200 to 400), the component manager 30 can integrally manage the networkDBs 2 and DB operation logic units 11. In FIG. 34, control apparatuses 1are configured by network DBs 2 and DB operation logic units 11 arrangedin a plurality of servers.

FIG. 35 illustrates a configuration of the component manager 30. In FIG.35, the component manager 30 includes a component information storageunit 31, a component management unit 32, an external control interfaceunit 33, and a component control interface unit 34.

The component information storage unit 31 stores configurations andconnection relationships of the network DBs and the DB operation logicunits 11 described in the above exemplary embodiment (for example, thecomponents 11A-11F described in the third to eighth exemplaryembodiments).

The component control interface unit 34 has a function as an interfacefor connection to the network DBs 2, the DB operation logic units 11,and the like. The component manager 30 accesses the network DBs 2 andthe DB operation logic units 11 via the component control interface unit34.

The component management unit 32 has a start and termination function320 for generating and deleting a network DB 2 and for starting andterminating a DB operation logic unit 11 in response to an operationfrom an operator. The component management unit 32 has a connectionfunction 321 for connecting components via the component controlinterface unit 34 in response to an operation from an operator. Thecomponent management unit 32 includes an alive monitoring function 322for monitoring whether the DB operation logic units 11 are properlyoperating. In addition, the component management unit 32 updates acontent of the component information storage unit 31 based on anoperation from the operator.

Process management units 9 in FIG. 34 are connected to the componentcontrol interface unit 34. For example, if DB operation logic units 11are configured on a plurality of servers as illustrated in FIG. 34, theprocess management units 9 execute management operations, includingstarting, terminating, and monitoring the DB operation logic units 11that operate on these servers, based on instructions from the componentmanagement unit 32. In addition, as illustrated in FIG. 34, theplurality of DB operation logic units 11 may be connected to differentnetworks (for example, an OpenFlow network and an MPLS (Multi-ProtocolLabel Switching) network).

Tenth Exemplary Embodiment

Next, a tenth exemplary embodiment of the present disclosure will bedescribed. FIG. 36 illustrates a configuration of a system according tothe tenth exemplary embodiment of the present disclosure. Hereinafter, auser interface 40 in FIG. 36 will be described with reference to thedrawings.

A server 400 illustrated in FIG. 36 has a function of configuring thecontrol apparatus 1 based on an operation of the user interface 40 usedby an operator.

The server 400 includes a display unit 401 and a management unit 402.The display unit 401 has a function of displaying icons corresponding toa network DB 2 and DB operation logic units 11 on the user interface 40(for example, on a screen displayed on a display). The management unit402 has a function of configuring the control apparatus 1 based on aconnection relationship of icons operated by an operator.

FIG. 37 illustrates a screen displayed by the display unit 401. Thescreen in FIG. 37 has a layout including a template display areadisplaying template icons corresponding to the above network DB 2 and DBoperation logic units 11 (for example, the components 11A-11F describedin the third to eighth exemplary embodiments) and a work area.

For example, if an operator drags and drops templates corresponding tonecessary network DBs 2, DB operation logic units 11, and the shortestpath logic unit 11D from the template display area in FIG. 37,corresponding icons are displayed in the work area. If an operatorconnects icons displayed in the work area, a connection line isdisplayed between the icons in the work area. For example, when thedisplay unit 401 receives a display request from an operator, detailedinformation about a network DB 2 or a DB operation logic unit 11 or anetwork topology generated by the visualization DB operation logic unit11B is displayed in an object display area using a pop-up window or thelike. For example, when the display unit 401 detects a click or the like(display request) on an icon in the work area, detailed informationabout a network DB 2 or a DB operation logic unit 11 or a networktopology generated by the visualization DB operation logic unit 11B isdisplayed in the object display area using a pop-up window or the like.

FIG. 38 is a diagram in which an operation executed via the userinterface 40 and a configuration of the control apparatus 1 configuredby the management unit 402 are associated with each other. Themanagement unit 402 can be configured by the component manager 30.

For example, the display unit 401 may display operation results of thenetwork DB 2 by a DB operation logic unit 11. For example, if an iconcorresponding to a DB operation logic unit 11 and an icon correspondingto a network DB 2 are connected to each other, the display unit 401displays operation results of the network DB 2 by the DB operation logicunit 11.

FIG. 38 illustrates a state in which an icon (NW-DB; corresponding to anetwork DB 2) TP1, an icon (OF-NW; corresponding to the OpenFlow controlunit 11A) TP2, and an icon (shortest path; corresponding to the shortestpath logic unit 11D) TP3 have been selected from the template displayarea. These icons are arranged and connected to each other in the workarea. In this way, the network DB 2, the OpenFlow control unit 11A, andthe shortest path logic unit 11D are added and connected to the controlapparatus 1. The network 4 corresponding to the network DB 2 iscontrolled by the OpenFlow protocol, and shortest path control isexecuted on the network 4.

FIG. 39 is a diagram in which an icon (visualization; corresponding tothe visualization DB operation logic unit 11B) TP4 is connected to theicon (NW-DB; corresponding to the network DB 2) TP1 in FIG. 38. In thisway, a network topology display function using a graph or the like isadded to the control apparatus 1.

FIG. 40 is a graph in which an icon (aggregation; the aggregation logicunit 11E) TP5 is additionally connected to the icon (NW-DB) TP1 to whichthe icon (OF-NW) TP2 is connected. The aggregation logic unit 11Ecorresponding to the icon (aggregation) TP5 aggregates and abstractstopology information in the network DB and stores the information inanother network DB 2. The icon (visualization) TP5 is connected to eachnetwork DB 2. As illustrated in FIG. 40, both a complex network topologyand an abstracted network topology can be displayed as graphs.

FIG. 41 is a graph in which an icon (slice; corresponding to the slicelogic unit 11C) TP6 is additionally connected to the icon (NW-DB) TP1 towhich the icon (OF-NW) TP2 is connected and logically-divided networkDBs are generated. In this way, a single network can be sliced to aplurality of virtual networks. In addition, by connecting various iconsin the template display area to the icons (NW-DB; network DBs)representing these sliced network DBs, the sliced networks can becontrolled and used individually.

FIG. 42 is a graph in which an icon (integration; corresponding to theintegration logic unit 11F) is connected to a plurality of icons (NW-DB)TP1 to which icons (OF-NW) TP2 are connected and a network DBintegrating these networks is generated. In this way, a plurality ofnetworks can be controlled and used as a single network.

As described above, by using the user interface according to the presentexemplary embodiment, an operator can customize initial settings orfunctions of the network control apparatus, without advanced knowledgeand skill. In addition, an operator may be allowed to set each network,refer to an entry of a network DB, and operate an entry via this userinterface 40. For example, it is preferable that an operator be allowedto modify a setting value or add, change, or delete an entry relating toa control (flow) operation by moving a cursor to a field in the objectdisplay area in FIG. 37.

While exemplary embodiments of the present disclosure have thus beendescribed, the present invention is not limited thereto. Furthermodifications, substitutions, or adjustments can be made withoutdeparting from the basic technical concept of the present invention. Forexample, the network configurations or the component configurations ineach drawing are merely used to facilitate understanding of the presentinvention. Namely, the present invention is not limited to theseconfigurations in the drawings.

In addition, for example, other than the variations of the DB operationlogic unit 11 described in the above exemplary embodiments, a networkextraction logic is applicable. With such logic, by partially extractinga topology of a single network DB and expanding the extracted topologyto another network DB, a flow of the network DB can be expanded to aflow of the original network DB. By connecting two network DBs in thisway, a function of partially controlling a network is added to thenetwork control apparatus. For example, another network operator can beallowed to operate only a part of a network or the routing algorithm ofonly that part can be changed.

In addition, while the above exemplary embodiments have been describedassuming that a real network is controlled, a network control unit thatlinks with a network simulator such as NS3 (Network Simulator version3)may be arranged. In this way, the network control apparatus can controlnot only a real physical network but also a network on a simulator.Thus, a network operator can test operations or performance of a networkcontrol apparatus created thereby on a simulator before applying thecontrol apparatus to a real physical network.

Finally, preferable modes of the present invention will be summarized.

<First Mode>

(See the control apparatus in the above first aspect)

<Second Mode>

In the control apparatus in the first mode, the interface unit operatesthe control information responsive to a common database operationcommand used by the plurality of modules.

<Third Mode>

In the control apparatus in the first or second mode, the interface unitcan configure control information which is based on the algorithm thatis different for each of the modules in the database.

<Fourth Mode>

In the control apparatus in any one of the first to third modes, theinterface unit refers to a condition preset by the database operationcommand issued by any one of the modules and notifies the module ofupdating of the control information when an updated content of thecontrol information matches the condition.<Fifth Mode>In the control apparatus in any one of the first to fourth modes, theinterface unit can configure control information that is based on acombination of the modules in the database.<Sixth Mode>In the control apparatus in any one of the first to fifth modes, thedatabase includes first information about a topology of the network andsecond information about a method of processing a packet in the network.<Seventh Mode>In the control apparatus in any one of the first to sixth modes, thedatabase includes third information for managing a packet that thecontrol apparatus receives from the network and fourth information formanaging a packet that the control apparatus transmits to the network.<Eighth Mode>In the control apparatus in any one of the first to seventh modes, theinterface unit is connectable to the modules that execute at least oneselected from the group consisting of path calculation betweencommunication terminals, management of a network topology, aggregationof a network topology, division of a network, or integration of anetwork.<Ninth Mode>(See the control method in the above second aspect)<Tenth Mode>In the control method in the ninth mode, the control information isoperated responsive to a common operation command used by the pluralityof modules.<Eleventh Mode>In the control method in the ninth or tenth mode, control informationwhich is based on the predetermined algorithm that is different for eachof the modules is configured in the database.<Twelfth Mode>In the control method in any one of the ninth to eleventh modes, acondition preset by the database operation command issued by any one ofthe modules is referred to and the module is notified of updating of thecontrol information when an updated content of the control informationmatches the condition.<Thirteenth Mode>In the control method in any one of the ninth to twelfth modes, controlinformation that is based on a combination of the modules is configuredin the database.<Fourteenth Mode>In the control method in any one of the ninth to thirteenth modes, firstinformation about a topology of the network and second information abouta method of processing a packet in the network is operated, the firstand second information being contained in the database.<Fifteenth Mode>In the control method in any one of the ninth to fourteenth modes, thedatabase includes third information for managing a packet that thecontrol apparatus receives from the network and fourth information formanaging a packet that the control apparatus transmits to the network,and the third information is operated responsive to the databaseoperation command issued by any one of the modules for processing thepacket.<Sixteenth Mode>In the control method in any one of the ninth to fifteenth modes, thecontrol information is operated by the modules that execute at least oneselected from the group consisting of path calculation betweencommunication terminals, management of a network topology, aggregationof a network topology, division of a network, or integration of anetwork.<Seventeenth Mode>(See the communication system in the above third aspect)<Eighteenth Mode>(See the program in the above fourth aspect)

The entire disclosure of the above NPL is incorporated herein byreference thereto. Modifications and adjustments of the exemplaryembodiments and examples are possible within the scope of the overalldisclosure (including the claims) of the present invention and based onthe basic technical concept of the present invention. Variouscombinations and selections of various disclosed elements (including theelements in each of the claims, exemplary embodiments, examples,drawings, etc.) are possible within the scope of the claims of thepresent invention. That is, the present invention of course includesvarious variations and modifications that could be made by those skilledin the art according to the overall disclosure including the claims andthe technical concept. The description discloses numerical value ranges.However, even if the description does not particularly disclosearbitrary numerical values or small ranges included in the ranges, thesevalues and ranges should be deemed to have been specifically disclosed.

REFERENCE SIGNS LIST

-   1 control apparatus-   2, 2A to 2F network database (network DB)-   3 node-   4 network-   4A management network-   9 process management unit-   10, 10-1 to 10-6 DB interface unit-   11, 11-1, 11-2 DB operation logic unit-   12 network control unit-   11A OpenFlow control unit-   11B visualization DB operation logic unit-   11C slice logic unit-   11D shortest path logic unit-   11E aggregation logic unit-   11F integration logic unit-   20 shortest path storage unit-   21 host information storage unit-   30 component manager (configuration management unit)-   31 component information storage unit-   32 component management unit-   33 external control interface unit-   34 component control interface unit-   40 user interface-   100, 200, 300, 400 server-   110 topology processing unit-   111 flow processing unit-   112 packet processing unit-   320 start and termination function-   321 connection function-   322 alive monitoring function-   401 display unit-   402 management unit-   TP1 to TP6 icon

What is claimed is:
 1. A control apparatus controlling a network, thecontrol apparatus comprising: a database which stores controlinformation for controlling the network; a plurality of modules, each ofwhich issues a database operation command so as to operate the databasebased on a predetermined algorithm; an interface unit which changes thecontrol information responsive to the database operation command issuedby any one of the modules; and a control unit which controls packetprocessing in the network based on the control information changed bythe interface unit, wherein a combination of the modules to be connectedto the interface unit is configured to be changed by an operator, andwherein, by changing the combination of the modules, the operatorconfigures the control apparatus suitable to a communication protocolused in the network.
 2. The control apparatus according to claim 1,wherein the interface unit operates the control information responsiveto a common database operation command used by the plurality of modules.3. The control apparatus according to claim 1, wherein the interfaceunit is adapted to configure control information which is based on thepredetermined algorithm that is different for each of the modules in thedatabase.
 4. The control apparatus according to claim 1, wherein theinterface unit refers to a condition preset by the database operationcommand issued by said any one of the modules and notifies the modulesof updating of the control information when an updated content of thecontrol information matches the condition.
 5. The control apparatusaccording to claim 1, wherein the interface unit is adapted to configurecontrol information that is based on the combination of the modules inthe database.
 6. The control apparatus according to claim 1, wherein thedatabase includes first information about a topology of the network andsecond information about a method of processing a packet in the network.7. The control apparatus according to claim 1, wherein the databaseincludes third information for managing a packet that the controlapparatus receives from the network and fourth information for managinga packet that the control apparatus transmits to the network.
 8. Thecontrol apparatus according to claim 1, wherein the interface unit isconnectable to the modules that execute at least one selected from agroup consisting of path calculation between communication terminals,management of a network topology, aggregation of a network topology,division of a network, and integration of a network.
 9. The controlapparatus according to claim 1, wherein the operator changes aconfiguration of the network by changing the combination of the modules.10. A control method of a control apparatus controlling a network, thecontrol method comprising: storing control information for controllingthe network in a database; issuing a database operation command, by eachof a plurality of modules, to operate the database based on apredetermined algorithm; changing, by an interface unit, the controlinformation responsive to the database operation command issued by anyone of the modules; and controlling packet processing in the networkbased on the control information changed by the interface unit, whereina combination of the modules to be connected to the interface unit isconfigured to be changed by an operator, and wherein, by changing thecombination of the modules, the operator configures the controlapparatus suitable to a communication protocol used in the network. 11.The control method according to claim 10, further comprising: operatingthe control information responsive to a common operation command used bythe plurality of modules.
 12. The control method according to claim 10,further comprising: configuring control information which is based onthe predetermined algorithm that is different for each of the modules inthe database.
 13. The control method according to claim 10, furthercomprising: referring to a condition preset by the database operationcommand issued by said any one of the modules; and notifying the modulesof updating of the control information when an updated content of thecontrol information matches the condition.
 14. The control methodaccording to claim 10, further comprising: configuring controlinformation that is based on the combination of the modules in thedatabase.
 15. The control method according to claim 10, furthercomprising: operating first information about a topology of the networkand second information about a method of processing a packet in thenetwork, the first and second information being contained in thedatabase.
 16. The control method according to claim 10, wherein thedatabase includes third information for managing a packet that thecontrol apparatus receives from the network and fourth information formanaging a packet that the control apparatus transmits to the network,and wherein the control method comprises: operating the thirdinformation responsive to the database operation command issued by saidany one of the modules for processing the packet.
 17. The control methodaccording to claim 10, further comprising: causing the modules thatexecute at least one selected from a group consisting of pathcalculation between communication terminals, management of a networktopology, aggregation of a network topology, division of a network, andintegration of a network to operate the control information.
 18. Acommunication system comprising a control apparatus controlling anetwork, the control apparatus comprising: a database which storescontrol information for controlling the network; a plurality of modules,each of which issues a database operation command so as to operate thedatabase based on a predetermined algorithm; an interface unit whichchanges the control information responsive to the database operationcommand issued by any one of the modules; and a control unit whichcontrols packet processing in the network based on the controlinformation changed by the interface unit, wherein a combination of themodules to be connected to the interface unit is configured to bechanged by an operator, and wherein, by changing the combination of themodules, the operator configures the control suitable to a communicationprotocol used in the network.
 19. A non-transitory computer-readablerecording medium storing a program causing a control apparatuscontrolling a network to execute: storing control information forcontrolling the network in a database; issuing a database operationcommand, by each of a plurality of modules, to operate the databasebased on a predetermined algorithm; changing, by an interface unit, thecontrol information responsive to the database operation command issuedby any one of the modules; and controlling packet processing in thenetwork based on the control information changed by the interface unit,wherein a combination of the modules to be connected to the interfaceunit is configured to be changed by an operator, and wherein, bychanging the combination of the modules, the operator configures thecontrol, apparatus suitable to a communication protocol used in thenetwork.